In a method for generating a selected word line voltage, a constant voltage that is substantially independent of a temperature change is generated. Additionally, a current that varies in proportion to a temperature is generated. To generate the selected word line voltage, the current is converted to a voltage that varies in proportion to the absolute temperature and the voltage is subtracted from the constant voltage.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for adjusting a selected word line voltage, comprising: measuring a first selected word line voltage generated by a word line voltage generator, the word line voltage generator being configured to generate the first selected word line voltage based on a constant voltage that is substantially independent of a temperature change; measuring a second selected word line voltage generated by the word line voltage generator, the word line voltage generator being configured to generate the second selected word line voltage based on the constant voltage and a current that varies in proportion to an absolute temperature; calculating a first temperature coefficient associated with the selected word line voltage based on the first and the second selected word line voltages; and changing a characteristic of a circuit element associated with the word line voltage generator to configure the word line voltage generator to generate the selected word line voltage with the first temperature coefficient that is substantially equal to a second temperature coefficient associated with a threshold voltage.
2. The method of claim 1 , wherein the changing the characteristic of the circuit element comprises changing a characteristic of a diode associated with a proportional to absolute temperature circuit, the proportional to absolute temperature circuit being configured to supply the current.
3. The method of claim 1 , wherein the changing the characteristic of the circuit element comprises changing a characteristic of a resistor associated with a proportional to absolute temperature circuit, the proportional to absolute temperature circuit being configured to supply the current.
4. The method of claim 1 , wherein the changing the characteristic of the circuit element comprises changing a characteristic of a resistor associated with a subtraction circuit, the subtraction circuit being configured to generate the selected word line voltage based on a difference between a voltage that varies in proportion to the absolute temperature and the constant voltage that is substantially independent of a temperature change.
5. The method of claim 1 , wherein the changing the characteristic of the circuit element is configured to adjust the first temperature coefficient associated with the selected word line voltage.
6. The method of claim 1 , wherein the first temperature coefficient associated with the selected word line voltage is defined by a difference between the first and second selected word line voltages divided by a difference between an absolute temperature of absolute zero and an absolute temperature associated with the selected word line voltage.
7. A method for adjusting a selected word line voltage, comprising: stopping a supply of a current that varies in proportion to an absolute temperature to a word line voltage generator, the word line voltage generator being configured to generate a first selected word line voltage absent the current; measuring the first selected word line voltage generated by the word line voltage generator; supplying the current to the word line voltage generator, the word line voltage generator being configured to generate a second selected word line voltage based on the current; measuring the second world line voltage generated by the word line voltage generator; calculating a first temperature coefficient associated with the selected word line voltage based on the first and second selected word line voltages; calculating a difference between the first temperature coefficient and a second temperature coefficient associated with a threshold voltage; and changing a supply of the current to the word line voltage generator to adjust the selected word line voltage generated by the word line voltage generator wherein the difference is substantially zero.
8. The method of claim 7 , wherein the changing the supply of the current comprises changing an electrical resistance of a resistor associated with a proportional to absolute temperature circuit, the proportional to absolute temperature circuit being configured to supply the current.
9. The method of claim 7 , wherein the changing the supply of the current comprises changing an emission coefficient of a diode associated with a proportional to absolute temperature circuit, the proportional to absolute temperature circuit being configured to supply the current.
10. The method of claim 7 , wherein the changing the supply of the current comprises increasing the supply of the current.
11. The method of claim 7 , wherein the changing the supply of the current comprises decreasing the supply of the current.
12. The method of claim 7 , wherein the stopping the supply of the current to the word line voltage generator configures the word line voltage generator to generate the first selected word line voltage with the absolute temperature of absolute zero.
13. The method of claim 7 , wherein the word line voltage generator is configured to generate the first selected word line voltage based on a constant voltage that is substantially independent of a temperature change.
14. The method of claim 7 , wherein the word line voltage generator is configured to generate the second selected word line voltage based on a difference between a voltage that varies in proportion to the absolute temperature and a constant voltage that is substantially independent of a temperature change.
15. The method of claim 7 , wherein the current is supplied to a subtraction circuit associated with the word line voltage generator.
16. A method for adjusting a selected word line voltage, comprising: stopping a supply of a current that varies in proportion to an absolute temperature to a word line voltage generator, the word line voltage generator being configured to generate a first selected word line voltage absent the current; measuring the first selected word line voltage generated by the word line voltage generator; calculating a first target selected word line voltage based on the first selected word line voltage and a temperature coefficient associated with a threshold voltage; supplying the current to the word line voltage generator, the word line voltage generator being configured to generate a second selected word line voltage based on the current; and increasing a supply of the current to the word line voltage generator to adjust the second selected word line voltage generated by the word line voltage generator wherein the second selected word line voltage is substantially equal to the first target selected word line voltage.
17. The method of claim 16 , further comprising: setting a control signal to a zero value; and incrementing the control signal to adjust a third selected word line voltage generated by the word line voltage generator wherein the third selected word line voltage is substantially equal to a second target selected word line voltage, wherein the first target selected word line voltage is based on the second target selected word line voltage and the temperature coefficient associated with the threshold voltage.
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April 21, 2006
April 14, 2009
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